Vehicles operating in an autonomous mode (e.g., driverless or self-driving) can relieve occupants, especially the driver, from some driving-related responsibilities. When operating in an autonomous mode, an autonomous vehicle can navigate to various locations using onboard sensors, allowing the vehicle to travel with minimal human interaction or in some cases without any passengers. Other than the objective situations of surrounding environments, autonomous vehicles also need to perceive the subjective intentions of other vehicles nearby in order to make the timely prediction and proper driving decisions. For example, the vehicle on the right lane is trying to change lane and occupy the space in front of an autonomous vehicle, it is probably not a good time for that autonomous vehicle to accelerate and one would expect braking might be needed shortly.
Traditionally, human drivers obtain such information through observing signal lights, mirrors or directly look over his/her shoulders. To exchange information between autonomous vehicles, direct communication through a local network is a more efficient and reliable way. However, it remains a challenging problem to establish and maintain such communication networks especially for autonomous vehicles.